1. Field of the Invention
The present invention relates to an antenna apparatus, and more particularly, to an antenna apparatus used for receiving radio waves for GPS (Global Positioning System) or satellite radio.
2. Description of Related Art
With the development of mobile communication devices and small communication devices (e.g., car navigation systems and portable navigation systems with GPS, satellite wave receivers, and the like) of recent years, it is required to miniaturize the antenna apparatus used for these devices and to enhance performance thereof.
In this regard, among antenna apparatuses, a flat antenna apparatus (e.g., circular polarized patch antenna or the like) has a merit that the apparatus is thin and small due to its structure, and it is relatively easy to integrate with a semiconductor circuit and thus, the flat antenna apparatus is widely applied as an antenna for small communication devices.
As such a flat antenna apparatus, there is known an antenna apparatus having a dielectric substrate comprising high dielectric such as ceramic, a radiating element provided on a surface of the dielectric substrate, and a circuit substrate (for example Japanese Patent Application Laid-open No. 2003-264424).
Such an antenna apparatus is provided with a power supply pin such as to pass through the dielectric substrate, the circuit substrate and a reflective element. The power supply pin is soldered and fixed to the antenna apparatus.
In recent years, antenna apparatuses in which a ceramic dielectric substrate is omitted and an antenna element formed of a metal plate is disposed on a circuit substrate at a distance therefrom have been developed. In the case of such an antenna apparatus, if the power supply pin passes through the circuit substrate and the antenna element and the power supply pin is soldered to the circuit substrate and the antenna element, a passing portion of the circuit substrate and a passing portion of the antenna element are soldered. However, if an attempt is made to solder one of the passing portions after the soldering operation of the other passing portion is completed, heat of the latter soldering operation of the one passing portion is transmitted to the other passing portion through the power supply pin. Consequently, solder of the other passing portion which was already solidified is melted when the one of the passing portions is soldered, and the power supply pin could drop in some cases.
Further, if a crack is generated in the soldered portion between the antenna element and the power supply pin due to external force after the soldering operation, there is a possibility that flow of current is hindered and desired antenna performance can not be exhibited.